In the manufacture of organic friction pads it has been considered essential that all water be removed from the composition of materials before curing the resin binder contained therein. If the water content is greater than 2% by weight of the composition of materials, the heat required to cure the resin in the composition of materials in evaporating the water can cause bubble marks and/or voids adjacent the surface of the friction pad. Therefore, all the ingredients in the composition of materials are dried before being mixed together to form a friction pad.
However, the density of the dry asbestos as compared to the other ingredients in the composition of materials requires substantial mixing before a uniform composition of materials is obtained. Unfortunately, such mixing causes a portion of the asbestos to become airborne and polute the surrounding environment. Often the amount of such airborne asbestos exceeds the allowable limits set in the United States by the Occupation Safety and Health Act of 1970. In an effort to maintain the quality of air within the allowable limits, most manufacturers have discovered that extensive air filtration systems are required in existing structures.